// message.vue
<template>
  <div>
    {{message}}
    <button @click="handleClick">Change word</button>
  </div>
</template>

<script>
export default {
  data() {
    return {
      message: "Hello World."
    };
  },
  methods: {
    handleClick() {
      this.message = "Hello Vue.";
    }
  }
};
</script>

<style>
</style>